Solid　oxide　electrolysis　cell　(SOEC)　can　perform　CO2　electrolysis　to　produce　CO　feedstock.　In　this　work,　we　show　Sr2Fe1.5+xMo0.5O6-delta　with　exsolved　Fe　nanoparticles　to　enhance　the　activity　to　CO2　electrolysis.　A　single　SOEC　with　a　configuration　of　SF1.5+xM-SDC/LSCM/LSM-SDC　shows　a　current　density　of　1.16　A　cm(-2)　at　1.8　V,　which　presents　the　CO　production　rate　of　6.85　mL　min(-1)　cm(-2)　and　the　current　efficiency　of　up　to　96.3%　at　850　degrees　C.　We　further　demonstrate　a　stable　electrolysis　performance　without　obvious　degradation　being　observed　even　after　a　long-time　operation　of　100　h.　The　exsolved　metal-oxide　interfaces　function　as　three　phase　boundary　which　transports　gas　molecules,　oxygen　ions　and　electrons　and　therefore　accommodate　CO2　splitting　in　electrochemical　process.　(C)　2020　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.